Method for forming a deposition film

Abstract

A method for forming a deposition film by introducing a source gas into a reduced pressure deposition chamber, establishing an electric field across opposing electrode to cause discharge in the deposition chamber, and decomposing or polymerizing the source gas by a discharge energy or the discharge energy and a thermal energy to form the deposition film on a substrate disposed in the deposition chamber, characterized by that an auxiliary substrate is provided in adjacent to the substrate.

What is claimed is: 
     
       1. A method for forming a deposition film by introducing source gas into a reduced pressure deposition chamber, establishing an electric field across opposing electrodes to cause discharge in said deposition chamber, and decomposing or polymerizing said source gas by a discharge energy or the discharge energy and a thermal energy to form the deposition film on a substrate disposed in said deposition chamber, wherein an auxiliary substrate is provided adjacent to said substrate, a material of said auxiliary substrate is similar to that of said substrate an area ratio of surfaces of said substrate and said auxiliary substrate contributing to the discharge is from 1/0.02 to 1/2, the temperature of said substrate is maintained between 200 to 400° C. during the deposition, said source gas comprises 5 to 40 volume percent SiH 4 , the pressure of said gas is from 0.1 to 0.2 Torr, and the flow rate of said source gas is 0.1 to 2 liters/minute. 
     
     
       2. A method for forming a deposition film according to claim 1 wherein a shape of said auxiliary substrate is similar to that of said substrate. 
     
     
       3. A method for forming a deposition film according to claim 1 wherein an assembly of said substrate and said auxiliary substrate serves as one of said opposing electrodes. 
     
     
       4. A method for forming a deposition film according to claim 3 wherein one of said opposing electrodes is located externally of said deposition chamber. 
     
     
       5. A method for forming a deposition film according to claim 3 wherein both of said opposing electrodes are inside of said deposition chamber. 
     
     
       6. A method for forming a deposition film according to claim 1 wherein said substrate is cylindrical. 
     
     
       7. A method for forming a deposition film according to claim 1 wherein one of said opposing electrodes is located externally of said deposition chamber. 
     
     
       8. A method for forming a deposition film according to claim 1 wherein both of said opposing electrodes are inside of said deposition chamber.